The present invention relates to a folding keyboard and, more particularly, to a folding keyboard for input especially applicable to electric portable devices such as personal digital assistants (PDAs) and mobile phones.
Along with the progress of information technology, automated equipment is gradually being supplied to every company and home, so that people have much more opportunities of dealing with keyboards. For instance, people use keyboards to communicate with computers, personal digital assistants (PDAs), mobile phones, and cash registers to input the instructions thereof.
In order to let keyboards be miniature and portable, folding keyboards have been proposed. However, in general a folding keyboard cannot be frontally folded, cannot show a whole arrangement of keys after being unfolded, or cannot be immediately used after being unfolded.
FIGS. 1 and 1A show a prior art folding keyboard proposed in U.S. Pat. No. 5,653,543, wherein a folding keyboard 10a is divided into a first key module 11a and a second key module 12a. The first and second key modules 11a and 12a are joined together by a plurality of connection parts 13a, so that they can be frontally folded, letting the keyboard be miniature and portable.
When the first and second key modules 11a and 12a of the above folding keyboard 10a are folded, circular arc faces are exploited for guidance, and they are turned along an axis 14a. Therefore, after the first and second key modules 11a and 12a are folded, they cannot be further shrunk to reduce the thickness. Moreover, multi-fold design cannot be accomplished, so that the miniature and portable functions of the keyboard cannot be further enhanced.
Accordingly, the prior art folding keyboard has inconvenience and drawbacks in practical use. The present invention aims to resolve the above problems.
The primary object of the present invention is to provide a folding keyboard, which can be frontally folded, can show a whole arrangement of keys after unfolded, and can be used immediately after unfolded, thereby enhancing convenience of use. Moreover, after the front faces of key modules burrow against each other, the key modules can be relatively shrunk to reduce the thickness, hence enhancing the miniature and portable functions of the keyboard.
To achieve the above object, the present invention provides a folding keyboard comprising a fixed key module and more than one mobile key modules. The fixed key module and the mobile key modules are joined together by links between them. Two ends of the links are joined at asymmetric positions at least between the fixed key module and one of the mobile key modules or between two of the mobile key modules. The mobile key modules can make relative motions with respect to the link and the fixed key module, so that the folding keyboard can be folded.
The various objects and advantages of the present invention will be more readily understood from the following detailed description when read in conjunction with the appended drawing, in which: